As an apparatus for measuring the internal information of a scattering medium such as a living body, an apparatus which uses pulse light transmitted inside the scattering medium, for example, an apparatus for measuring a scattering medium by using time resolved spectroscopy (TRS) such as an optical mammography apparatus is available. A time-resolved waveform of light measured by the above-described apparatus includes not only response time characteristics of a scattering medium which is a measurement object but also response time characteristics (instrumental function) of the apparatus itself. Therefore, in carrying out an analysis of data, it is necessary to eliminate the influence of the instrumental function from a measurement waveform, that is, to correct the data.
In existing optical mammography apparatuses, actually measured instrumental functions are used to correct data. When measuring an instrumental function, it is necessary to remove many optical fibers for irradiation and detection installed on a gantry unit, fix a module for measuring the instrumental function in place of the optical fibers and install the optical fibers on the gantry unit again after completion of measurement of the instrumental function. Therefore, this method poses a problem that prolongs the working time and measurement time.
In order to solve the above problem, a method described in Patent Literature 1 by which a measurement waveform of a scattering medium which is a measurement object is corrected without using an instrumental function has been proposed. According to this method, the measurement waveform of the scattering medium which is the measurement object, a measurement waveform of a scattering medium for reference with known optical coefficients (an absorption coefficient and a scattering coefficient) and the theoretical waveform thereof are used to correct the measurement waveform of the scattering medium which is the measurement object. Thereby, it is possible to acquire the internal information of the scattering medium more easily, with the influence of the instrumental function taken into account.